extract from plant parts (e.g. starch, pectin, cellulose)
Factors affect gum properties
molecular weight
monosaccharide composition
type of chains
number of side chains
distribution of side chains
Main Hydrocolloids - Thickeners
xanthan gum
carboxymethylcellulose
methylcellulose and hydroxypropyl cellulose
galactomannas (guar and LBG)
Main hydrocolloids - Gelling agent
Thermoreversible gelling agents
gelatin
agar
kappa carrageenan
iota carrageena
low methoxy (LM) pectin
gellan gum
Thermally irreversible gelling agents
alginate
high methoxyl (HM) pectin
konjac mannan
locust bean gum
Pectin
derived from peel of citrus fruits, apple pomace, sugar beet, sunflower heads.
types of pectin---High methoxyl pectin (HMP), DE> 50%
- High methoxyl pectin (HMP)
DE---58% to 75%
to form gel, soluble solid content 55-85%, pH 2.8-3.8. (e.g. jam and jellies)
ultrarapid/rapid set (DE as high as 77)---used in jam with whole fruits, to ensure uniform distribution of fruits particles.
slow set (DE~58) ---used in very acid fruits such as blackcurrant to avoid premature gelation.
Low methoxyl pectin (LMP) - DE < 50% — two sub-groups: Conventional low methoxyl pectin (LMP) and Amidated low methoxyl pectin (ALMP) - Form gels in the presence of Ca2+, with a low solids content & wide pH range (1-7) [but soluble solids can be up to 85%] - LMP – less Ca2+ reactive than ALMP ⇒ used as a thickening agent in yoghurt fruit - ALMP – very Ca2+ reactive ⇒ assist gelation in low sugar fruit preparations, e.g. low-sugar jams & jellies
Carrageenan
- Carrageenan is a highly refined extract of seaweed from the rhodophyta family. - Chemically its composition is a long chain of galactose residues linked, resulting in a long chain of high molecular weight. a) Iota Carrageenan - It is extracted from Eucheuma Spinosum seaweed. b) Lambda Carrageenan - It is extracted from Gigartina, Iriadeae and Chondrus crispus seaweed. c) kappa Carrageenan - It is a extracted from Eucheuma cottonii and from Chondrus crispus seaweed.
Alginate
- Derived brown seaweed (Laminaria hyperborea)
- Made up of blocks of Dmannuronic acid (M-blocks) & Lguluronic acid (G-block) - Alginate gels are heat- and freeze/thaw-stable, and can be prepared at very low solids and low temperatures with moderate shear. - Alginates work well as stabilizers in a wide variety of food applications, and are particularly useful in the formulation of restructured fruits and vegetables.
Guar Gum
- Derived from guar (Cyamopsis tetragonolobus) seeds, this long, rigid, linear molecule of beta-1,4-D-galactomannans with alpha-1,6-linked D-galactose. - This galactomannan is soluble in cold water, hydrating quickly to produce viscous pseudoplastic solutions that, although shear-thinning, generally have greater low-shear viscosity than other hydrocolloids. - It is stable over a wide pH range, but will degrade at pH extremes at high temperature. The molecules’ interfacial binding allows guar to act as an emulsifier. - Guar gum binds water and retards ice-crystal growth.
Gum Arabic
- An exudate from the Acacia senegal tree, gum arabic is comprised of arabinogalactan and a lesser amount of polysaccharide/ protein complexes. - It is very water-soluble (except at a pH lower than 3), compatible with high solids and provides low viscosity with Newtonian flow at concentrations below 40%. - Its applications include encapsulating flavors, emulsifying beverages, clarifying wine, coating candy shells and controlling water. - Gum acacia seyal comes from the Acacia seyal tree and is used for coatings and encapsulation.
Locust Bean Gum
- Also called carob gum, as it’s derived from carob (Ceratonia siliqua) seeds, locust bean gum (LBG) has an irregularly shaped molecule with branched beta-1,4-D-galactomannan units. - This neutral polymer is only slightly soluble in cold water; it requires heat to achieve full hydration and maximum viscosity. - LBG finds use mainly in dairy products, particularly ice cream, where it protects against heat shock and imparts a desirable mouthfeel. - It can also act as a binder in meats and stabilize sauces, gravies and dressings.
Xanthan Gum
- A fermentation product of Xanthomonas campestris bacteria, xanthan gum develops a weak gel for high-viscosity solutions at low concentration that show little effect in the temperature range from 0° to 100°C. It is pseudoplastic (shear-reversible) over broad shear rate and concentration ranges, but imparts a stringy texture. - Xanthan has excellent solubility in hot or cold mediums, exhibits stability to heat and pH and in the presence of high salt concentrations, and resists many enzymes. - This gum is often used to thicken and stabilize emulsions, foams and suspensions in applications including sauces and dressings.
week 1 -5
What is Hydrocolloid?
The term ‘hydrocolloids’ - to a range of polysaccharides and proteins (also known as ‘water soluble gums’ or just ‘gums’.)
Primary functions- Thickening agents, Gelling or texturizing agents
Secondary functions- Stabilization of emulsions, suspension of particulates, control of crystallisation, encapsulation, formation of film
Main classes of hydrocolloids
Factors affect gum properties
Main Hydrocolloids - Thickeners
Main hydrocolloids - Gelling agent
Thermoreversible gelling agents
Thermally irreversible gelling agents
Pectin
- High methoxyl pectin (HMP)
Low methoxyl pectin (LMP)
- DE < 50% — two sub-groups: Conventional low methoxyl pectin (LMP) and Amidated low methoxyl pectin (ALMP)
- Form gels in the presence of Ca2+, with a low solids content & wide pH range (1-7) [but soluble solids can be up to 85%]
- LMP – less Ca2+ reactive than ALMP ⇒ used as a thickening agent in yoghurt fruit
- ALMP – very Ca2+ reactive ⇒ assist gelation in low sugar fruit preparations, e.g. low-sugar jams & jellies
Carrageenan
- Carrageenan is a highly refined extract of seaweed from the rhodophyta family.- Chemically its composition is a long chain of galactose residues linked, resulting in a long chain of high molecular weight.
a) Iota Carrageenan - It is extracted from Eucheuma Spinosum seaweed.
b) Lambda Carrageenan - It is extracted from Gigartina, Iriadeae and Chondrus crispus seaweed.
c) kappa Carrageenan - It is a extracted from Eucheuma cottonii and from Chondrus crispus seaweed.
Alginate
- Derived brown seaweed (Laminaria hyperborea)- Made up of blocks of Dmannuronic acid (M-blocks) & Lguluronic acid (G-block)
- Alginate gels are heat- and freeze/thaw-stable, and can be prepared at very low solids and low temperatures with moderate shear.
- Alginates work well as stabilizers in a wide variety of food applications, and are particularly useful in the formulation of restructured fruits and vegetables.
Guar Gum
- Derived from guar (Cyamopsis tetragonolobus) seeds, this long, rigid, linear molecule of beta-1,4-D-galactomannans with alpha-1,6-linked D-galactose.- This galactomannan is soluble in cold water, hydrating quickly to produce viscous pseudoplastic solutions that, although shear-thinning, generally have greater low-shear viscosity than other hydrocolloids.
- It is stable over a wide pH range, but will degrade at pH extremes at high temperature. The molecules’ interfacial binding allows guar to act as an emulsifier.
- Guar gum binds water and retards ice-crystal growth.
Gum Arabic
- An exudate from the Acacia senegal tree, gum arabic is comprised of arabinogalactan and a lesser amount of polysaccharide/ protein complexes.- It is very water-soluble (except at a pH lower than 3), compatible with high solids and provides low viscosity with Newtonian flow at concentrations below 40%.
- Its applications include encapsulating flavors, emulsifying beverages, clarifying wine, coating candy shells and controlling water.
- Gum acacia seyal comes from the Acacia seyal tree and is used for coatings and encapsulation.
Locust Bean Gum
- Also called carob gum, as it’s derived from carob (Ceratonia siliqua) seeds, locust bean gum (LBG) has an irregularly shaped molecule with branched beta-1,4-D-galactomannan units. - This neutral polymer is only slightly soluble in cold water; it requires heat to achieve full hydration and maximum viscosity.- LBG finds use mainly in dairy products, particularly ice cream, where it protects against heat shock and imparts a desirable mouthfeel.
- It can also act as a binder in meats and stabilize sauces, gravies and dressings.
Xanthan Gum
- A fermentation product of Xanthomonas campestris bacteria, xanthan gum develops a weak gel for high-viscosity solutions at low concentration that show little effect in the temperature range from 0° to 100°C. It is pseudoplastic (shear-reversible) over broad shear rate and concentration ranges, but imparts a stringy texture.- Xanthan has excellent solubility in hot or cold mediums, exhibits stability to heat and pH and in the presence of high salt concentrations, and resists many enzymes.
- This gum is often used to thicken and stabilize emulsions, foams and suspensions in applications including sauces and dressings.